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    <title>GROOPS - Gravityfield2TimeSplines</title>

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            <h1>Gravityfield2TimeSplines</h1><p>

This program estimates splines in time domain from a time variable gravity field
and writes <a class="groops-class" href="fileFormat_timeSplinesGravityField.html">outputfileTimeSplines</a>.
The <a class="groops-class" href="gravityfieldType.html">gravityfield</a> is sampled at <a class="groops-class" href="timeSeriesType.html">sampling</a>, converted to potential coefficients
in the range between <strong class="groops-config-element">minDegree</strong> and <strong class="groops-config-element">maxDegree</strong> inclusively.
The time series of spherical harmonics can be temporal filtered with <a class="groops-class" href="digitalFilterType.html">temporalFilter</a>.</p><p>In the next step temporal splines with <strong class="groops-config-element">splineDegree</strong> and nodal points given
at <a class="groops-class" href="timeSeriesType.html">splineTimeSeries</a> are adjusted to the time series in a least squares sense.
This is very fast for block means (splineDegree = 0) but for other splines a large systems of equations
must be solved. In the adjustment process the time series of gravity fields can be interpreted as samples
at the given times or as continuous function with linear behaviour between sampled points (<strong class="groops-config-element">linearInterpolation</strong>).</p><p>To combine a series of potential coefficients to a spline file with block means (splineDegree = 0)
use the fast <a class="groops-program" href="PotentialCoefficients2BlockMeanTimeSplines.html">PotentialCoefficients2BlockMeanTimeSplines</a> instead.
</p>
<table class="table table-hover">
<tr class="table-primary"><th>Name</th><th>Type</th><th>Annotation</th></tr>
<tr class="table-light"><td class="m-0"><div class="h-100 config-tree depth-0"><div class="h-100 config mustset">outputfileTimeSplines</div></div></td><td>filename</td><td></td></tr>
<tr class=""><td class="m-0"><div class="h-100 config-tree depth-0"><div class="h-100 config mustset-unbounded">gravityfield</div></div></td><td><a href="gravityfieldType.html">gravityfield</a></td><td></td></tr>
<tr class="table-light"><td class="m-0"><div class="h-100 config-tree depth-0"><div class="h-100 config optional-unbounded">temporalFilter</div></div></td><td><a href="digitalFilterType.html">digitalFilter</a></td><td>filter sampled gravity field in time</td></tr>
<tr class=""><td class="m-0"><div class="h-100 config-tree depth-0"><div class="h-100 config optional">minDegree</div></div></td><td>uint</td><td></td></tr>
<tr class="table-light"><td class="m-0"><div class="h-100 config-tree depth-0"><div class="h-100 config optional">maxDegree</div></div></td><td>uint</td><td></td></tr>
<tr class=""><td class="m-0"><div class="h-100 config-tree depth-0"><div class="h-100 config optional">GM</div></div></td><td>double</td><td>Geocentric gravitational constant</td></tr>
<tr class="table-light"><td class="m-0"><div class="h-100 config-tree depth-0"><div class="h-100 config optional">R</div></div></td><td>double</td><td>reference radius</td></tr>
<tr class=""><td class="m-0"><div class="h-100 config-tree depth-0"><div class="h-100 config mustset-unbounded">sampling</div></div></td><td><a href="timeSeriesType.html">timeSeries</a></td><td>gravity field is sampled at these times</td></tr>
<tr class="table-light"><td class="m-0"><div class="h-100 config-tree depth-0"><div class="h-100 config optional">removeMean</div></div></td><td>boolean</td><td>remove the temporal mean of the series before estimating the splines</td></tr>
<tr class=""><td class="m-0"><div class="h-100 config-tree depth-0"><div class="h-100 config optional">linearInterpolation</div></div></td><td>boolean</td><td>assume linear behavior between sampled points</td></tr>
<tr class="table-light"><td class="m-0"><div class="h-100 config-tree depth-0"><div class="h-100 config mustset">splineDegree</div></div></td><td>uint</td><td>degree of splines</td></tr>
<tr class=""><td class="m-0"><div class="h-100 config-tree depth-0"><div class="h-100 config mustset-unbounded">splineTimeSeries</div></div></td><td><a href="timeSeriesType.html">timeSeries</a></td><td>nodal points of splines in time domain</td></tr>
</table>

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